Field of the Invention
The present invention relates to a respiratory abnormality improvement apparatus for preventing or alleviating respiratory abnormalities such as sleep apnea and infrequent respiration during sleep by applying an electric stimulus to a patient's living body.
Description of Related Art
As a respiratory abnormality improvement apparatus for treating respiratory abnormalities during sleep by applying an electric stimulus to a mentalis muscle, there are proposed a method for applying an electric stimulus in synchronization with sleep apnea and infrequent respiration during sleep; and a method for continuously applying a monotonous electric stimulus regardless of conditions of the sleep apnea and infrequent respiration during sleep.
As the former method, U.S. Pat. No. 5,190,053, for example, discloses a configuration in which a respiratory effort and an intrathoracic pressure of a patient are monitored by a sensor, and when it is found through a comparison between a condition detected by the sensor and a threshold that a patient had fallen into a respiratory difficulty, electric signals are applied for a given period of time to stimulate the patient's muscle. Further, as the latter method, Japanese Patent No. 4960704 discloses a configuration in which a stimulus signal out of synchronization with an apneic condition is applied to a patient in such a manner as to alternate, for a given length of time, a conduction period where a group of electric pulses composed of a plurality of electric pulses is generated and a break period where no group of electric pulses is generated.